This invention relates to a new and unexpectedly synergistic insecticidal composition containing the commercial insecticides phosmet and diflubenzuron, and particularly containing these compounds in a weight ratio of from about 1:3 to about 3:1.
Phosmet is the generic name of the commercial insecticide N-(mercaptomethyl)phthalimide S-(O,O-dimethylphosphorodithioate), which has the formula ##STR1## and is disclosed for instance, in U.S. Pat. No. 2,767,194. This compound is sold under several trademarks including the registered trademark Imidan.RTM. and Prolate.RTM..
Diflubenzuron is the generic name for the commercial insecticide N-[[(4-chlorophenyl)amino]carbonyl]-2,6-difluorobenzamide, which has the formula ##STR2## and is sold under the name Dimilin.RTM..
Both of these insecticides have been in commercial use for some years and have been registered for use against various insects. Diflubenzuron, in particular, is known to control insects by causing inhibition of molting.
As substantiated by test results which follow, it has been determined that a combination of these two insecticides, in a weight ratio of from about 3:1 to about 1:3, and particularly from about 3:1 to about 1:1, of phosmet:diflubenzuron, possesses unexpected activity in controlling insects, particularly the larvae of the cabbage looper, (Trichoplusia ni), beet armyworm, (Spodoptera exigua), and tobacco budworm (Heliothis virescens), and other insects of this same genera.